My prior U.S. Pat. Nos. 3,608,891 and 3,734,488 disclose and claim a machine known as a "rocker hopper" which is especially well suited for feeding bulky newspaper sections at a predetermined, metered rate of delivery as part of an overall system for assembling and collating various sections of a big city newspaper. The rocker hopper disclosed in such patents utilizes an oscillating gripper pad that underlies the bottom-most article in the hopper and oscillates through both a reverse stroke and a subsequent forward stroke during each cycle of operation. As the rocker swings rearwardly, it engages the bottom surface of the lowermost article and thus pulls a leading marginal edge of the article off of a forwardly located shelf which supports the front margin of the stack. This has the effect of separating the leading edge of the lowermost edge of the article from the rest of the stack.
Then, as the rocker swings forwardly, the separated leading edge of the lowermost article is presented to a pair of nip rollers that grab the article and quickly pull it completely out of the stack, feeding it to the main collating line or other part of the system.
While the oscillating rocker pad performs extremely well for bulky, multiple page newspaper sections, it is not well-suited for dispensing thin, single-sheet articles such as advertising fliers and the like. When folded newspaper sections are dispensed, they are arranged in the hopper with their "hard" folded edge leading and with the two halves of the section superimposed upon one another. Thus, as the rocker sweeps rearwardly in engagement with the bottom half of the newspaper section and pulls it rearwardly off the front shelf, the upper half of the newspaper necessarily moves along with it due to the interconnection presented by the folded edge. However, when thin, single-sheet articles are involved, it is difficult for the rocker pad to overcome the significant frictional drag between the lowermost article and the next higher article. Consequently, there is a tendency to feed "doubles" or "triples", instead of only one sheet at a time.